CHEMISTRY 244 - Organic Chemistry Laboratory II Spring 2019 Lab #1: Oxidation of Alcohols to Ketones - Borneol Oxidation (2 weeks) Purpose. In this lab you will learn about oxidation reactions in organic chemistry, and apply this reaction to the oxidation of a secondary alcohol (borneol) to a ketone (camphor) using the green oxidizing agent, Oxone. You will purify the product by extraction and sublimation, determine purity by mp, and measure reaction efficiency by calculating % yield. Important Notes: 1) You must have lab goggles and your Hayden-McNeil Lab Notebook as specified in the lab syllabus. The format for writing in your notebook is outlined below. You should continue using your notebook from CHEM 243, or you can purchase a lab notebook from Dr. Brush (DMF 407) for $10 (50 pages). Lab goggles ($10) are sold by the chemistry club. 2) This is Part I of a two-week lab, and the pre-lab work for Part I is outlined below. In Part I you will meet your lab partner, check-in, review the syllabus with your recitation instructor, and get an overview of the experiment. You and your lab partner will then begin Part I of the experiment. Be prepared for a pre-lab quiz. Your notebook pages will be submitted at the conclusion of Part II. 3) Format your lab notebook items I - IV as outlined below. Enter the page number for Lab #1 Part I in your Table of Contents. If you are using your lab notebook from CHEM 243, just continue your Table of Contents where you left off, with a heading of CHEM 244 Spring 2019. Enter the page number for Lab #1 Part I, and go to that page and continue with the following headings: I. Your name, the name of your lab instructor, the name of your lab partner. II. Title of the experiment and date. III. Table of Reagents (Parts I & II). Synthesis experiments require a table with the first column listing the Chemical Name of all reagents, roughly in the order in which they are used in the experimental procedure. That is followed by a column with the Chemical Formula, and a column of the Purpose of the reagent (i.e., reactant, drying agent, solvent, etc.). For everything you identified as Reactant, Product, or Solvent, you will also need columns for: structure, molecular weight, and physical properties (melting point, boiling point, density). Copy the sample table below into your notebook, and fill in the required information. Refer back to your reagent tables from CHEM 243 for assistance. Chemical Name Purpose chemical formula structure molecular mass (g/mole) melting point ( o C) boiling point ( o C) density (liquids) (g/ml) Borneol N/A N/A Ethyl acetate Sodium chloride stabilizer N/A N/A N/A N/A N/A Oxone (see background) N/A N/A N/A N/A Water N/A Sodium bisulfite reducing agent N/A N/A N/A N/A N/A Magnesium sulfate N/A N/A N/A N/A N/A Camphor N/A N/A N/A IV. Background information and notes from the pre-lab assignment. You are expected to read this lab handout, prepare this notebook section with the following content, and review this information to prepare for a prelab quiz. 1) Goals. Based on your reading, what are the Experimental Goals for Part I of this experiment? 2) Lab Safety Parts I & II. Copy the table outlined below into your lab notebook. Read over the experimental procedure for Parts I & II, then complete the table so that you have a thorough list of key lab safety topics specific to this lab. Parts of the table have been completed for you.
What is the specific Risk? What is the associated Hazard? (burn, sharp/cuts, solvent vapor, skin irritant, eye irritant, etc.) How will you limit Exposure to the hazard? SDS Section 2 summary SDS Section 8 summary Hot plate Hazardous chemicals Volatile solvents Glassware Melting point capillary tube Electrical equipment Vacuum filtration Chemical exposure may result in irritation and or illness Cuts from broken glass Glassware implodes under vacuum Keep solvent covered; use in hood Look for frayed power cords; avoid spilling water InfraRed Light Oxone Health & Safety (look up SDS at Flinn website) 3) Balanced reaction. Under your reagent table draw the balanced reaction based on the scheme detailed in this handout. 4) Oxidation and Reduction Reactions in Organic Chemistry. This lab introduces you to oxidation and reduction reactions in organic chemistry. As we have not yet covered these reactions in class, you will need to either: Look up and read about alcohol oxidations and carbonyl reductions in organic chemistry, or Watch this lecture video on Dr. Brush s web site: CH 12-1: Introduction & Alcohol RedOx (https://www.youtube.com/watch?v=jk4tbl-gutm&feature=youtu.be) Based on your reading and/or the video, complete the following oxidation/reduction reactions in your lab notebook. For each reaction identify the type of reactant (1 o, 2 o, or 3 o alcohol OR an aldehyde or ketone), give the oxidizing (Ox) reagent or reducing (Red) reagent, and draw the structure of the organic product. Your notebook is now prepared to start the lab period. Be sure to leave space in your notebook to take notes during the recitation period.
Background. Oxone is a green oxidizing reagent for the preparation of ketones from secondary alcohols. Oxone is the commercial name for a triple salt with the formula 2KHSO 5 KHSO 4 K 2SO 4. The oxidizing agent is peroxymonosulfate, KHSO 5, which is also used in sanitizing swimming pools. A general scheme for the reaction is shown below: Part I Experimental Procedure. This experimental procedure was developed by BSU student Evan McDaid (2016). It has been adapted from Wissinger et.al. (J. Chem. Educ. (2011), 88, 652-656). Qualitative Observations. You are expected to record detailed observations for all steps in this experiment. You will be graded on the accuracy and completeness of these observations, which you will use to answer post-lab questions. Step 1: Setting up the Reaction Mixture. To a 20 ml reaction vial with a stir bar, add 0.50 g borneol, 2.0 ml ethyl acetate, and 0.75 ml of a solution of NaCl in deionized water (0.053g NaCl/mL). Start vigorous stirring of the reaction mixture, then add 1.2 g Oxone to start the reaction. It is normal if some solids do not dissolve. Stir for 20 minutes, then add an additional 0.283 ml of the NaCl solution and stir for an additional 10 minutes. Step 2: Quenching the Reaction. Add 7.5 ml of deionized water to the reaction mixture to dissolve the inorganic salts. Next add a spatula tip of sodium bisulfite to reduce any excess Oxone. Step 3: Extraction of Crude Camphor. Add 1.0 ml of ethyl acetate to the reaction vial, cap and gently mix the contents, venting from time to time. Allow the organic and aqueous layers to separate, then use a glass pipette to transfer the organic layer into a 5 ml reaction vial. Extract the aqueous layer twice more, each time with 1.0 ml of ethyl acetate. Combine all ethyl acetate solutions in the same reaction vial. Step 4: Isolation of Crude Camphor. Dry the combined ethyl acetate layers over anhydrous magnesium sulfate, then use a glass pipette to transfer the dried ethyl acetate solution to a pre-weighed 25 ml vacuum flask. Evaporate the solvent in the sand bath in the hood at 35 o C with a gentle stream of Argon gas (15 minutes). CAUTION: Excessive heating or Argon gas flow will result in sublimation of the product and a low yield. After the solvent has evaporated a solid should remain. Record the appearance of your crude product and determine its mass. Do not remove the product from the flask. It I not necessary to determine the melting point of the crude product. Cover all openings to the flask with parafilm, label your flask, and save for purification and IR analysis next week. V. Quantitative Observations. Using the suggested format below, build Data, Result and IR tables in your lab notebook. Immediately after your tables show all calculations with clearly labeled headings. These tables will be completed in Parts I & II. Data Table for Lab #1 Parts I & II Oxidation of Borneol Sample Molecular mass (g/mole) Exact mass (grams) Borneol Oxone peroxymonosulfate, KHSO 5 Crude camphor Sublimed camphor (Part II) Calculations: Volume (ml) Moles Limiting reagent? (place an X)
Results Table for Lab #1 Parts I & II Oxidation of Borneol Sample Theoretical yield (grams) Theoretical yield (moles) Crude camphor Sublimed camphor (Part II) % Recovery % Yield Melting point range ( o C) Literature melting range ( o C) Calculations: IR Data Table for Lab #1 Part II Oxidation of Borneol (Complete after Part II of this lab). Sample Structure Key functional groups and IR bands Borneol (example) Alcohol, 3200-3600 cm -1 Camphor Sublimed product Post-Lab Questions for Part I. (1) Which step in the Part I procedure gave you the most trouble and why? (2) Using complete sentences and your observations, data and results, discuss your evidence that the product you synthesized is not a pure compound. (3) % Yield is calculated by taking the mass or moles of product, divided by the theoretical mass or moles of product (x100). What type of useful information can you get from the % Yield? Based on that answer, what is your % Yield from Part I telling you? (4) Read over Part II of this lab. Get started on the pre-lab work. You will not tear out your notebook pages for Part I. However, before you leave lab you must have your lab instructor check your notebook and initial the last page. Continued
CHEMISTRY 244 - Organic Chemistry Laboratory II Spring 2019 Lab #1 (Part II): Oxidation of Alcohols to Ketones - Borneol Oxidation Purpose. In this lab you will learn about oxidation reactions in organic chemistry, and apply this reaction to the oxidation of a secondary alcohol (borneol) to a ketone (camphor) using the green oxidizing agent, Oxone. You will purify the product by extraction and sublimation, determine purity by mp, and measure reaction efficiency by calculating % yield. Important Notes: 1) You must have lab goggles and your Hayden-McNeil Lab Notebook as specified in the lab syllabus. The format for writing in your notebook is outlined below. 2) This is Part II of a two-week lab and the pre-lab work for Part II is outlined below. Be prepared for a pre-lab quiz. Your notebook pages from Parts I & II will be submitted at the conclusion of the lab. 3) Format your lab notebook items I - IV as outlined below. I. Your name, the name of your lab instructor, the name of your lab partner. II. Title of the experiment and date. III. Table of Reagents. (Just review your Part I table) IV. Background information and notes from the pre-lab assignment. You are expected to read this lab handout, prepare this notebook section with the following content, and review this information to prepare for a prelab quiz. 1) Goals. Based on your reading, what are the Experimental Goals for Part II of this experiment? 2) Lab Safety. Review your lab safety table from Part I. 3) Sublimation. In Part II of this lab you will use the new technique of sublimation to purify your crude product from Part I. Look up sublimation in organic chemistry and write a 2-3 sentence summary that describes the use of this technique in the organic chemistry laboratory. 4) Sublimation Apparatus. The following URL (University of Calgary Department of Chemistry) has a diagram of a sublimation apparatus very similar to what you will use in lab. Read the PDF document and sketch and label the complete apparatus (http://tinyurl.com/z95r3eb). Your notebook is now prepared to start the lab period. Be sure to leave space in your notebook to take notes during the recitation period. Part II Experimental Procedure. Qualitative Observations. You are expected to record detailed observations for all steps in this experiment. You will be graded on the accuracy and completeness of these observations, which you will use to answer post-lab questions. Step 1: Sublimation. Set up the sublimation apparatus as described by your recitation instructor, with a cold finger and vacuum hose. Wrap the flask in Al foil for insulation. Clamp the apparatus on a hot plate, and connect to the vacuum. Fill the cold finger with ice water, but be VERY careful that the water does not drip down the outside of the test tube. Turn on the vacuum and set the hotplate to heat the sample to 75-80 o C (digital hotplate setting of 90-100). You may want to heat a small beaker with water and clamped thermometer alongside of the apparatus. You will need to periodically replace the water in the cold finger with additional ice water. Sublimation should take no longer than one hour. Step 2: Isolation of Pure Product. Once the crude camphor has sublimed onto the cold finger, remove the flask from the hotplate, remove the Al foil, and carefully release the vacuum. Use a pipette to remove water from the cold finger. Carefully remove the cold finger and scrape the pure product into a pre-weighed beaker or watch glass. Record the appearance of your product and determine its mass and melting point. Heat the sample slowly! Quickly bring the Mel- Temp to within 30 o C of the expected melting point, then heat at no more than a 1 o C rise every 10 seconds.
Step 3: Obtain an IR spectrum of your camphor product and compare it to the borneol starting material. V. Quantitative Observations. Complete the Data and Result tables you started in Part I of this lab. Don t forget to show all calculations with clearly labeled headings. Complete the IR table based on the structure of borneol and camphor, and the IR spectrum of your purified product. Post-Lab Questions for Part II. (1) Using complete sentences and your observations, data and results, discuss your evidence that the product you synthesized is a pure compound. (2) % Recovery is calculated by taking the mass of pure product, divided by the mass of crude product (x100). What type of useful information can you get from the % Recovery? Based on that answer, what is your % Recovery telling you? (3) % Yield is calculated by taking the mass or moles of product, divided by the theoretical mass or moles of product (x100). What type of useful information can you get from the % Yield? Based on that answer, what is your % Yield telling you? (4) Discuss whether the IR data are consistent with your product. Be sure to staple a copy of your IR spectrum with your notebook pages.